1. Field of the Invention
This invention relates to integrated circuits and, more particularly, to sense amplifier test circuits.
2. Description of the Related Art
Circuits such as sense amplifiers may detect very small differential voltages at their input, and output a digital value that corresponds to the differential input. For example, in a memory cell such as a static random access memory (SRAM) having a pair of differential bit lines connected to a sense amplifier, the sense amplifier is used to detect the difference between the bit lines. Depending on the process parameters during manufacturing, it may be possible for the SRAM cells to have very small differential voltage outputs. In addition, the sense amplifiers themselves may have varying thresholds between manufacturing lots. This variability may present reliability problems.
The manufacturing of integrated circuits is a complex process. Bringing a new circuit design to a fabrication facility, or bringing an existing circuit design to a new fabrication facility may require a number of characterization steps to establish a device library. Depending on the process technology, and the complexity of the circuits, there may be several iterations of process adjustments to ensure reliable operation of the manufactured devices. In many cases, there may be several revisions of silicon before the design is fully operational. Accordingly, it may be desirable to provide a robust circuit design while reducing the number of iterations of process adjustments, particularly during device and process characterization.